Combination electrical pickup and bridge for guitars and other instruments



Noml, 1949. E. HARKER 2,436,647

COMBINATION E CTRICAL PICKUP AND BRIDGE FOR GUITARS AND OTHERINSTRUMENTS Fil ed Feb. 8, 1946 L m I INVENTOR.

ATTD RN EYE! Patented Nov. 1, 1949 COMBINATION ELECTRICAL PICKUP ANDBRIDGE FOR GUITARS AND OTHER IN- STRUMENTS William Ernest Harker, IdahoFalls, Idaho Application February 8, 1946, Serial No. 646,406

1 Claim.

This invention relates to a combination electrical pickup and bridge fora guitar -or other string instruments and the main object of theinvention is to provide a device for picking up the vibrations of thesteel strings on a stringed instrument, and by use of an amplifierproduce a stronger musical tone.

The device can be installed on the musical instrument without damagingor cutting the instrument. It will replace the conventional bridge andit can be removed at any time and replaced by the conventional bridge ifan amplifier is not available. The device is retained in place by thepressure of the strings and uses the principle of induction as thestrings vibrating in the magnetic field induce alternating current in acoil mounted on the device. These currents are fed toan amplifier whichreproduces the vibrations in a speaker in the form of music or sound.

By the use of this device any instrument using steel strings may be madeinto an electric instrument since only the vibrations of the strings areamplified.

With the above and other objects and advantages in view the inventionconsists of the novel details of construction, arrangement andcombination of parts more fully hereinafter described, claimed andillustrated in the accompanying drawing in which:

Figure 1 is a plan view of an embodiment as applied to a stringedinstrument and connected to an amplifier;

Figure 2 is a side view of the device partly in elevation and partlybroken away;

Figure 3 is a sectional view on the line 3-3 of Figure 1;

Figure 4 is a sectional view on the line 44 of Figure 1 and Figure 5 isa sectional view on the line 55 of Figure 1.

Referring more in detail to the drawing the reference numeral l0designates a permanent magnet fastened at each end to the pole pieces l2and M respectively by welding [3 Or the like.

The pole piece I4 is provided with slots l6 which are relatively spacedto receive the strings N3 of the instrument 2!], thus the pole piece I4functions as a bridge for the instrument. The strings I8 pass over thepole piece I2 but are never in contact with it.

A coil 22 of very fine magnet wire is wound on the magnet l0 and thestarting end of the coil is grounded on the pole piece 12 at 24.

The free end of the coil is connected to an amplifier 26 by means of ashielded microphone cord 28 having a plug 3!! for insertion into theinput of the amplifier. The shield of the cord is also grounded on thedevice at 32 on the pole piece l4.

A cover 34 of insulating material is provided on the coil 34 and servesto protect the cord from damage.

The precise construction of amplifier 26 does not necessarily constitutea part of the invention, since any conventional amplifier may be usedwhen available.

The device can be constructed to be used with an instrument having anynumber of strings. The length of the permanent magnet can be varied asdesired and if the pole piece I4 is lowered it can be used withoutremoving the conventional bridge.

In the device the strings become part of the magnetic path of thepermanent magnet, since the bridge poles are made of soft iron andcomplete the magnetic circuit. The vibration of the strings alternatelyincrease and decrease the magnetic field, thus inducing an alternatingor pulsating electro-magnetic piece which can be amplified to reproducethe musical tones of the strings.

The device can be made in any size and shape to fit the instrument withwhich it is to be used and it does not stop the vibrations of the bodyof the instrument which gives the instrument its tone.

It is believed that the operation and construction of my device will beapparent to those skilled in the art and it is to be understood thatchanges in details of construction, arrangement and combination of partsand the size thereof may be resorted to providing they fall within thespirit of the invention and the scope of the appended claim.

Having thus described the invention what is claimed as new and desiredto be secured by Letters Patent is:

A pickup for use with a stringed musical instrument comprising apermanent bar magnet, pole pieces secured by welding to said magnet atthe opposite sides thereof so that said pole pieces will elevate saidmagnet above said instrument, one of said pole pieces being of a greaterheight than the other-of said pole pieces, the former of said polepieces having relatively spaced slots in the upper edge thereof toreceive the strings of the instrument and serve as a bridge for saidstrings to maintain said strings in proper relation to said instrumentfor the playing thereof and to maintain said strings in a plane above 3the lower pole piece when said pickup is positioned beneath the stringsof said instrument, a coil of fine magnet Wire Wound on said pole piece,the starting end of said coil being grounded to said lower pole piece, ashielded microphone cord connecting the opposite end of said coil to anamplifier, said cord being grounded to said first pole piece, and acovering of insulating material on said coil for the protection thereof.

WILLIAM ERNEST HARKER.

REFERENCES CITED The following references are of record in the file ofthis patent:

Number Number UNITED STATES PATENTS Name Date Kentner Oct. 30, 1934Beniofi Apr. 29, 1941 FOREIGN PATENTS Country Date Great Britain 1935

